The present invention relates to a stage mechanism for use in a semiconductor lithography exposure apparatus and, in particular, to a stage mechanism for use in a scan-type exposure apparatus and an EUV exposure apparatus which use an electron beam and operate within a vacuum chamber.
Conventionally, to cope with a semiconductor device whose density has been intensified, there is developed an electron beam drawing apparatus which draws an electron beam directly on a wafer (for example, xe2x80x9cElectron Beam Drawing Apparatusxe2x80x9d, SEAJ Journal, 24-32, December, 1995). Here, FIGS. 20 and 21 are respectively longitudinal section views of a stage mechanism employed in a conventional electron beam drawing apparatus. In a guide portion 102a of a stage 102 which is disposed in the interior portion of a vacuum chamber 101 in such a manner that it is contacted with the chamber interior portion, conventionally, there is employed a rolling guide system. However, because this rolling guide system is a guide system of a contact type, there are produced minute vibrations when the stage 102 is moved, which has an ill effect on the electron beam drawing operation of the stage mechanism. Also, such movement of the stage 102 causes dust, heat and wear, which results in the degraded accuracy of the electron beam drawing operation. Further, the rolling guide system requires some oil lubrication, that is, oil must be always supplied in order to prevent the environment of the interior of the vacuum chamber from being worsened.
A motor 105 serving as an actuator is disposed at a position distant from a wafer mounting surface 102b of the stage 102, that is, at a position existing outside the vacuum chamber 101.
The stage 102 can be driven by the motor 105 disposed outside the vacuum chamber 101 through a ball screw 103, a ball screw receiver 104, and a rotary shaft 106 connected to the ball screw 103. In the portion of the vacuum chamber 101 through which the rotary shaft 106 penetrates, there is employed a rotary magnetic seal 107 which uses magnetic fluid so as to keep the vacuum of the interior portion of the vacuum chamber 101. Therefore, special care must be given to generation of a magnetic field by the rotary magnetic seal 107.
FIG. 21 shows a conventional electron beam drawing apparatus in which a ball screw is not used but a direct-acting rod 108 is connected to a stage and thus the stage can be driven through the direct-acting rod 108. By the way, in FIG. 21, the stage disposed in the interior portion of the vacuum chamber 101 shown in FIG. 20 is omitted. Actually, the stage can be driven through the direct-acting rod 108 by a drive stage 109 and a drive motor 105 respectively disposed outside the vacuum chamber 101. In the portion of the vacuum chamber 101 through which the direct-acting rod 108 penetrates, there is disposed a bellows-like bellows 110 in order to be able to keep the vacuum of the interior portion of the vacuum chamber 101; however, the bellows 110 must be structured such that it can be expanded and contracted so as to properly follow the movement of the drive stage 109. Since the expansion and contraction amount of the bellows 110 per one ridge thereof is small, in order to be able to follow the moving amount of the drive stage 109, it is necessary to use a long bellows-like bellows which has a large number of ridges. For this reason, in the conventional electron beam drawing apparatus shown in FIG. 21, there is found a drawback that the moving accuracy of the stage is worsened due to the contracting resistance of the long bellows-like bellows 110.
In the conventional electron beam drawing apparatus, there are also found other drawbacks that, since a given pattern is drawn on a wafer by scanning an electron beam, the drawing speed is slow and also that, when compared with a stepper system capable of collective transfer using the light, or a step and scan system capable of scanning and exposing a reticle and a wafer synchronously according to the magnification of projection optics, the number of wafers to be processed per hour (that is, throughput) is low.
Thus, to make up for the above-mentioned drawbacks of the electron beam drawing apparatus, there is developed a scan-type exposure apparatus using an electron beam (Lloyd R. Harriot, xe2x80x9cScattering with angular limitation projection electron beam lithography for suboptical lithographyxe2x80x9d, J. Vac. Sci. Technol. B15, 2130 (1997)).
Recently, the electron beam drawing apparatus is requested that the accuracy of its stage mechanism should be enhanced so as be able to cope with the narrowed width of a drawing line and also that the stage mechanism should be enhanced in speed and acceleration in order to be able to gain the throughput. However, in the stage mechanisms respectively shown in FIGS. 20 and 21, due to use of the rolling guide system, the sliding resistance on the guide surface is large which makes it difficult to enhance the accuracy of the stage mechanism; and, enhancement in the speed and acceleration of the stage mechanism increases the wear amount of the stage mechanism to a great extent, which gives rise to the greatly shortened life of the stage mechanism.
Also, while the electron beam drawing apparatus requires a loader which is used to deliver a wafer or a reticle, in the conventional stage mechanisms respectively shown in FIGS. 20 and 21, it is difficult to secure a space for installation of the loader. Further, the electron beam drawing apparatus requires an optical length measuring device which is used for positioning control and thus it is also necessary to secure a space for installation of the length measuring device.
The present invention aims at eliminating the above-mentioned drawbacks found in the conventional stage mechanisms. Accordingly, it is a first object of the invention to provide a stage mechanism for use in a vacuum chamber which employs a non-contact static pressure bearing as a sliding surface thereof to thereby be able not only to increase the speed, acceleration and life of the stage mechanism but also to maintain its high accuracy over a long period of time.
Also, it is a second object of the invention to provide a stage mechanism which, in spite of employment of a non-contact static pressure bearing as a sliding surface thereof, can keep the vacuum environment of the interior portion of the vacuum chamber and thus can maintain a clean environment.
Further, it is a third object of the invention to provide a non-contact slide apparatus for use in a vacuum which can fulfill the requirements for maintaining a drawing accuracy such as non-magnetism, low vibration, and low dust generation, and a stage mechanism for use in such non-contact slide apparatus for use in a vacuum.
Still further, it is a fourth object of the invention to provide a stage mechanism in which a Y slide shaft penetrates through only one side surface of the wall surfaces of a vacuum chamber to thereby allow the remaining wall surfaces to provide free spaces, so that a delivery system such as a wafer loader or a reticle loader can be easily disposed in these free spaces and also there can be easily secured a sufficient space for provision of an optical length measuring device.
In attaining the above objects, according to a first aspect of the invention, there is provided a slide apparatus for use in a vacuum, comprising: two slide shafts disposed so as to penetrate through a vacuum chamber; an X stage base plate connected to the slide shafts within the vacuum chamber; air slide bearings disposed outside the vacuum chamber and in the vicinity of the penetration portions of the slide shafts for guiding their associated slide shafts; bellows respectively for covering the penetration portions of the vacuum chamber for penetration of the slide shafts and the end faces of the air slide bearings opposed to the penetration portions of the vacuum chamber for penetration of the slide shafts to thereby prevent gas from flowing into the vacuum chamber; and, an actuator disposed outside the vacuum chamber, wherein each of the air slide bearings includes, on the slide surface thereof with respect to its associated slide shaft, air pads for floating up the present slide shaft using gas, and exhaust grooves for discharging the gas from the air pads, whereby, in a state where the slide shafts are floated up by the air slide bearings, the actuator drives the X stage base plate through the slide shafts.
According to a second aspect of the invention, there is provided a slide apparatus for vacuum, comprising: a slide shaft disposed so as to penetrate through a vacuum chamber; an X stage base plate connected to the slide shaft within the vacuum chamber; a drive rod connected to the X stage base plate and penetrating through the wall of the vacuum chamber; an actuator disposed outside the vacuum chamber and connected to the drive rod; an air slide bearing disposed outside the vacuum chamber and in the vicinity of the penetration portion of the slide shaft for guiding the slide shaft; a first bellows covering the penetration portion of the slide shaft and the end face of the air slide bearing opposed to the penetration portion of the slide shaft for preventing gas from flowing into the vacuum chamber; and, a second bellows covering the penetration portion of the drive rod shaft and the end face of the actuator opposed to penetration portion of the drive rod for preventing the air from leaking into the vacuum chamber, wherein the air slide bearing includes, on the slide surface thereof with respect to the slide shaft, an air pad for floating up the slide shaft using gas, and a gas discharge groove for discharging the gas from the air pad, whereby, in a state where the slide shaft is floated up by the air slide bearing, the actuator drives the X stage base plate through the slide rod.
According to a third aspect of the invention, there is provided a slide apparatus for use in a vacuum, comprising: two X slide shafts disposed in parallel to each other on the two sides of a vacuum chamber with the vacuum chamber between them; X air slide bearings for guiding their associated X slide shafts; two Y air slide bearings respectively disposed on their associated X slide shafts along the same straight line in a direction perpendicular to the X slide shafts; two Y slide shafts respectively penetrating through the vacuum chamber with their associated Y air slide bearings as their guides for holding a stage base plate within the vacuum chamber; two fixed plates respectively disposed on the outer wall of the vacuum chamber so as to surround the openings of the vacuum chamber through which the Y slide shafts penetrate through the vacuum chamber; two movable plates respectively disposed opposed to their associated fixed plates on the end faces of the Y air slide bearings on the vacuum chamber side thereof for covering the openings of the vacuum chamber; first air pads disposed on the slide surfaces of the fixed plates with respect to the movable plates for floating up the movable plate using compressed gas; first exhaust grooves formed in the slide surfaces of the fixed plates so as to surround the openings of the fixed plates, for discharging the compressed gas; second air pads disposed on the slide surfaces of the Y air slide bearings with respect to the Y slide shafts for floating up the Y slide shafts using compressed gas; second gas discharge grooves formed nearer to the openings of the vacuum chamber than the second air pads in the slide surfaces of the Y air slide bearings so as to surround the Y slide shafts, for discharging the compressed gas supplied to the Y air slide bearings by the air pads; third air pads disposed on the slide surfaces of the X air slide bearings with respect to the X slide shafts for floating up the X slide shafts using compressed gas; and, at least two actuators respectively disposed outside the vacuum chamber, wherein, in a state where the X slide shafts are floated up, the X slide shafts are driven by one of the two actuators and, in a state where the Y slide shafts are floated up, the Y slide shafts are driven by the other actuator.
According to a fourth aspect of the invention, there is provided a slide apparatus for use in a vacuum, comprising: two X-axis air slide plates respectively disposed in parallel to each other on the two sides of a vacuum chamber with the vacuum chamber between them; two support portions respectively including two fixed plates for holding their respective X-axis air slide plates between them; two Y air slide bearings disposed on their respective X-axis air slide plates so as to extend on the same straight line in a direction perpendicular to the X-axis air slide plates; two Y slide shafts penetrating through the vacuum chamber with the Y air slide bearings as the guides thereof for holding a stage base plate within the vacuum chamber; first air pads disposed on the two X-axis air slide plates for supplying compressed gas for floating up the two X-axis air slide plates onto the slide surfaces of the two X-axis air slide plates with respect to the support portions; first exhaust grooves respectively formed on the slide surfaces of the X-axis air slide plates with respect to the fixed plates on the vacuum chamber side so as to surround the openings of the vacuum chamber through which the Y slide shafts penetrate, for exhausting the compressed gas; second air pads disposed on the slide surfaces of the Y air slide bearings with respect to the Y slide shafts for floating up the Y slide shafts using compressed gas; second exhaust grooves disposed in the slide surfaces of the Y air slide bearings nearer to the bellows than the second air pads so as to surround the Y slide shafts, for exhausting the compressed gas used by the second air pads; and, at least two actuators respectively disposed outside the vacuum chamber, wherein, in a state where the two X-axis air slide plates are floated up, the two X-axis air slide plates are driven by one of the two actuators and, in a state where the two Y slide shafts are floated up, the two Y slide shafts are driven by the other actuator.
According to a fifth aspect of the invention, there is provided a stage mechanism for use in a vacuum, comprising: a Y slide shaft penetrating through only one side surface of the wall surfaces of a vacuum chamber for holding a stage base plate disposed within the vacuum chamber in a cantilevered manner; a Y air slide bearing disposed outside the vacuum chamber for guiding the Y slide shaft; an X air slide plate fixed to the end face of the Y air slide bearing on the vacuum chamber side thereof and movable in a direction perpendicular to the Y slide shaft; a first X air slide bearing for supporting the X air slide plate while holding the same from above and below as well as from right and left in a non-contact manner; a coupling portion disposed on the end face of the Y slide shaft situated outside the vacuum chamber and movable in parallel with the X air slide plate for transmitting a drive force given by a Y-axis actuator; a second X air slide bearing serving as a guide of the coupling portion; first air pads disposed on the slide surface of the Y slide bearing opposed to the Y slide shaft for floating up the Y slide shaft using compressed gas; first exhaust grooves formed in the slide surface of the Y air slide bearing nearer to the vacuum chamber than the first air pad so as to surround the Y slide shaft, for exhausting the compressed gas from the first air pad; second air pads disposed on the X air slide plate for supplying compressed gas for floating up the X air slide plate to the slide surface of the X air slide plate with respect to the First X air slide bearing; and, second discharge grooves formed on the slide surface of the X air slide plate with respect to a fixed plate of the first X air slide bearing situated on the vacuum chamber side thereof so as to surround an opening formed in the fixed plate, for exhausting the compressed gas from the second air pad, wherein, in a state in which the Y slide shaft is floated up, a stage is driven by the Y actuator and, in a state in which the X air slide plate and coupling portion are floated up, the stage is driven by an X-axis actuator.
According to a sixth aspect of the invention, there is provided a stage mechanism for vacuum, comprising: a Y slide shaft penetrating through only one side surface of the wall surfaces of a vacuum chamber for holding, in a cantilevered manner, a stage base plate disposed within the vacuum chamber; a Y air slide bearing disposed outside the vacuum chamber for serving as a guide for the Y slide shaft; an X air slide plate fixed to the end face of the Y air slide bearing on the vacuum chamber side thereof and movable in a direction perpendicular to the Y slide shaft; a first X air slide bearing for supporting the X air slide plate while holding the same from above and below as well as from right and left in a non-contact manner; an X slide shaft used to support the Y air slide bearing and movable in parallel to the X air slide plate; a second X air slide bearing for serving as a guide of the X slide shaft; a coupling portion disposed on the end face of the Y slide shaft situated outside the vacuum chamber for transmitting a drive force given by a Y-axis actuator, the coupling portion being movable in parallel to the X air slide plate and X slide shaft as they move; first air pads disposed on the slide surface of the Y air slide bearing with respect to the Y slide shaft for floating up the Y slide shaft using compressed gas; first exhaust grooves formed in the slide surface of the Y air slide bearing nearer to the vacuum chamber than the first air pads so as to surround the Y slide shaft, for exhausting the compressed gas from the first air pads; second air pads disposed on the X air slide plate for supplying compressed gas for floating up the X air slide plate to the slide surface of the X air slide plate with respect to the first X air slide bearing; and, second exhaust grooves formed in the slide surface of the X air slide plate with respect to a fixed plate of the first X air slide bearing situated on the vacuum chamber side thereof so as to surround an opening formed in the fixed plate, for exhausting the compressed gas from the second air pads, wherein, in a state in which the Y slide shaft is floated up, a stage is driven by the Y-axis actuator and, in a state in which the X air slide plate and the X slide shaft are floated up, the stage is driven by an X-axis actuator.
According to a seventh aspect of the invention, there is provided a stage mechanism for use in a vacuum, comprising: a Y slide shaft penetrating through only one side surface of the wall surfaces of a vacuum chamber for holding, in a cantilevered manner, a stage base plate disposed within the vacuum chamber; a Y air slide bearing disposed outside the vacuum chamber for serving as a guide of the Y slide shaft; two X air slide plates fixed in parallel to each other to the two ends of the air slide bearing and movable in a direction perpendicular to the Y slide shaft; two X air slide bearings respectively for supporting their associated X air slide plates while holding the same from above and below as well as from right and left in a non-contact manner; a coupling portion disposed on the end face of the Y slide shaft situated outside the vacuum chamber for transmitting a drive force given by a Y-axis actuator, the coupling portion being movable in parallel to the X air slide plate and X slide shaft as they move; first air pads disposed on the slide surface of the Y air slide bearing with respect to the Y slide shaft for floating up the Y slide shaft using compressed gas; first exhaust grooves formed in the slide surface of the Y air slide bearing nearer to the vacuum chamber than the first air pads so as to surround the Y slide shaft, for exhausting the compressed gas from the first air pads; second air pads disposed on the X air slide plate for supplying compressed gas for floating up the X air slide plate to the slide surface of the X air slide plate with respect to the first X air slide bearing; and, second exhaust grooves formed in the slide surface of the X air slide plate with respect to a fixed plate of the first X air slide bearing situated on the vacuum chamber side thereof so as to surround an opening formed in the fixed plate, for exhausting the compressed gas from the second air pads, wherein, in a state in which the Y slide shaft is floated up, a stage is driven by the Y-axis actuator and, in a state in which the two X air slide plates are floated up, the stage is driven by an X-axis actuator.
According to an eighth aspect of the invention, there is provided a stage mechanism for use in a vacuum, comprising: two slide shafts respectively disposed in parallel to each other at given intervals so as to penetrate slidably through a vacuum chamber; a stage base plate disposed within the vacuum chamber, connected to the two slide shafts so as to bridge over them, and mounting a rotary stage thereon; air slide bearings respectively disposed outside the vacuum chamber and fitted with their associated slide shafts so as to be able to guide the two slide shafts; a first actuator disposed outside the vacuum chamber for driving or moving the two slide shafts, wherein, on the slide surfaces of the air slide bearings with respect to the slide shafts, there are disposed first air pads for floating up their respective slide shafts using compressed gas and exhaust grooves for exhausting the compressed gas from the first air pads; the rotary stage includes a spindle for mounting a test piece thereon, an air bearing for the spindle, and a second actuator for driving or rotating the spindle; and, the air bearing includes, on the slide surface thereof with respect to the spindle, second air pads for floating up the spindle using compressed gas and exhaust portions for exhausting the compressed gas from the second air pads, whereby, while the slide shafts are floated up, the slide shafts are driven or moved by the first actuator and, while the spindle of the rotary stage is floated up, the spindle of the rotary stage is driven or moved by the second actuator.
According to the eighth embodiment of the invention, by supplying the compressed gas to the air slide bearings, the two slide shafts are floated up and thus the two slide shafts are carried by their respective bearings in a non-contact manner. In a state where the slide shafts are floated up in this manner, the slide shafts are driven or moved by the first actuator. Also, by supplying the compressed gas to the air bearing, the spindle of the rotary stage is floated up and the spindle is thereby carried by the bearing in a non-contact manner. In a state where the spindle is floated up in this manner, the spindle is driven or rotated by the second actuator. As a result of this, the sample carried on the spindle is moved by the slide shafts moving in a non-contact manner and also by the spindle of the rotary stage rotating in a non-contact manner, so that a desired pattern is drawn on the sample by irradiation of an electron beam.